1. Field of the Invention
This invention relates to a mobile device having a plurality of ground engaging wheels, a load supporting platform and a hand control for varying the angle defined by the platform and the ground. More specifically, this invention relates to a lawn edger device and the like.
2. Information Disclosure Statement
The average usage of a motorized lawn edger is eight hours per year. Because of the considerable stress imposed upon a lawn edger during operation of the same, the useful life of a motorized edger is forty hours. Therefore, on the average, a lawn edger must be repaced every five years and this imposes a relatively heavy financial burden on a person responsible for lawn maintenance.
In an effort to increase the ruggedness of construction of conventional lawn edgers, the handle has been fabricated as a relatively massive and reinforced structure in order to withstand the strain of manual variation of the depth of cut of the cutter blade. Usually, a system of arms and levers connect the cutter blade housing to the handle so that by manually pivoting a lever on the handle, the depth of cut can be controlled. In the prior art devices, if the handle were not of massive construction, there would exist a tendency for the arms and levers to buckle under the stress of vibration and when the cutter is cutting through relatively thick root systems. The heavy and reinforced structure of traditional edger handles increases the cost of manufacture of the same and the present invention provides a device for adjustably varying the depth of cut of the cutter blade of a lawn edger that avoids the need of such costly handles.
The adjustable depth hand control of the present invention overcomes the aforementioned inadequacies of the prior art devices by providing a simple and low cost pawl and ratchet mechanism that permits the variable adjustment of the cutter blade relative the ground or the like.
Although the prior art lawn edgers provide a reliable mechanism for adjusting either the depth of cut of the cutter blade relative the lawn and the angle at which the edge is cut, the prior art proposals have been relatively expensive to produce. It is the primary object of the present invention to provide a variably adjustable depth hand control for a lawn edger or the like that overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which significant contributes to the ease with which such lawn edgers can be made and therefore the low cost of production of the same.
In our prior patent application Ser. No. 537,072 filed Sept. 29, 1983, now U.S. Pat. No. 4,532,998 the invention disclosed therein solved many of the problems of the prior art. However, the invention disclosed therein was limited in adjustment only in a cutting depth direction. It is an object of the present invention to further improve upon our prior invention by enabling adjustment both for cutting depth and angle of the cutting blade.
Another object of the present invention is the provision of a lawn edger having a relatively lightweight handle and hand control for variably adjusting the depth of the cutter blade relative the ground.
Another object of the present invention is the provision of a lawn edger having a platform with first wheel means connected to the first end of the platform and with a first arm having second wheel means pivotally mounted to the second end of the platform with a connecting arm varying the rotatable position of the first arm relative to the platform to vary the height of the second end of the platform relative to the ground.
Another object of the present invention is the provision of a lawn edger having a connecting arm including a portion having a plurality of teeth for cooperating with a locking plate for variably fixing the disposition of the second end of the platform relative the ground.
Another object of the present invention is the provision of a lawn edger having a relatively lightweight handle which is rigidly connected to and extends angularly relative to the platform.
Another object of the invention is the provision of a lawn edger having a motor or an engine disposed on the platform whereby the motor or engine moves in unison with the adjustment of the cutter blade.
Another object of this invention is the provision of a lawn edger wherein the motor or engine is fixedly mounted relative to the cutter blade enabling the motor or engine to move in unison with the cutter blade upon adjustment of the depth of the cutter blade.
Another object of this invention is the provision of a lawn edger wherein the weight of the motor or engine is directly translated to effect downward pressure on the cutter blade.
Another object of this invention is the provision of a lawn edger wherein the connecting arm may be readily fabricated and assembled.
Another object of the present invention is the provision of a lawn edger which simplifies the interconnection between the motor or engine and the cutting blade.
Another object of the invention is the provision of a lawn edger wherein the depth of the cutting blade relative to the ground may be efficiently and positively controlled and wherein the stress of maintaining the cutting blade in a selected position is absorbed by a toothed portion of the connecting arm and a locking plate secured to the platform.
Another object of the present invention is the provision of a lawn edger in which a plurality of ground-engaging wheels maintain the frame of the edger at a constant distance from the ground and a motive means support platform and cutter blade support means are both pivotally secured to the frame of the edger.
Another object of the present invention is the provision of a lawn edger having a cutter blade support means and a position retaining means pivotally connected to the support means, the retaining means cooperating with the frame for varying the pivotal disposition of the cutter blade support means relative to the frame for variably adjusting the depth of the cutter blade relative to the ground.
Another object of the present invention is the provision of a lawn edger having a hand control means connected to the position retaining means for remotely controlling the disposition of the position retaining means relative to the frame for adjustably varying the depth of the cutter blade relative to the ground.
Another object of the present invention is the provision of a lawn edger having a handle pivotally secured to the frame such that the handle pivots from a first position for storage and shipping of the edger to a second position in which the handle is disposed substantially upright for permitting hand control of the lawn edger during use.
Another object of the present invention is the provision of a lawn edger including a position retaining means and a clutch means for selectively permitting the cutter blade to be driven by the motive means.
Another object of the present invention is the provision of a lawn edger having a platform for supporting the motive means and a cutter blade support means such that the platform and the support means pivot about the same pivotal axis.
Another object of the present invention is the provision of a lawn edger having a debris flap rigidly secured to the cutter blade support means for preventing debris being thrown rearwardly from the cutter blade.
Another object of the present invention is the provision of a lawn edger having a position retaining means including a third arm having a plurality of indentations along the length thereof and stop means extending from the frame for selectively cooperating with one of the plurality of indentations for variably adjusting the pivotal disposition of the cutter blade relative to the frame.
Another object of the present invention is the provision of a lawn edger in which the hand control means includes an elongated rod having a proximal and a distal end, the proximal end of the rod being pivotally secured to the position retaining means and the distal end of the rod slidably cooperating with the distal end of the handle such that movement between the rod and the handle results in movement of the position retaining means relative to the frame for varying the depth of the cutter blade relative to the ground.
Another object of the present invention is the provision of a lawn edger having a handle and a locking means removably extending within aligned holes defined respectively by the handle and the frame.
Another object of the present invention is the provision of a lawn edger having clutch means further including a foot-operated lever and an extension of the platform cooperating with the lever, with a biasing means extending between the lever and the motive means, and lost motion means disposed respectively at the end of the lever and the extension such that when the lever is pivoted by application of pressure to one end of the lever in use of the edger, the lever pivots in opposition to the biasing means to urge the extension and the platform from a first position of the platform in which the motive means is drivingly connected to the cutter blade to a second position of the platform in which the motive means is disconnected from the cutter blade.
Another object of the present invention is the provision of a clutch means which includes a drive pulley and a driven pulley rigidly connected respectively to the motive means and the cutter blade, and a drive belt cooperating with the pulleys for selectively driving the cutter blade.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the invention. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings. This invention should not be construed as limited to lawn edgers but should include ground tillers, rotary trench cutters, road line markers, sports field marking machines and the like.